Marine mammals often aggregate and forage in specific ‘hotspot’ areas, which are associated with the predictability of prey sources driven by certain oceanographic processes. However, our understanding of the interactions between marine predators and the oceanographic processes remains incomplete, particularly in near-coastal and estuarine regions. This study investigated how predictable oceanographic processes influence the distribution patterns of Indo-Pacific humpback dolphins (Sousa chinensis) foraging in a known hotspot within the Pearl River Estuary, characterized by the complex topography of its manmade harbor and the interplay between strong tidal flows and river plumes. To address the fine-scale spatial distribution pattern of dolphin foraging, we conducted fixed passive acoustic monitoring of foraging ‘buzzes’ both inside and outside the harbor. Additionally, boat-based transect surveys were conducted to explore the relationship between dolphin foraging and associated water properties and current fields driven by oceanographic processes. Temporal trend analyses of buzzes revealed a pronounced tidal-related pattern in dolphin foraging activity, with increased detections during ebbing tides outside the harbor. Transect surveys indicated areas with elevated chlorophyll and turbidity levels attracted more dolphins during flood tides, whereas regions with high surface salinity gradients were preferred by dolphins during ebb tides. Oceanographic analysis recognized these bio-physical links as indicators of oceanographic features, including chlorophyll-rich river plumes, converging fronts, and shear-induced turbulence. These features enhance prey abundance and availability for humpback dolphins. This study highlights that oceanographic processes are crucial for determining the fine-scale spatiotemporal distribution of foraging in coastal dolphins, and offers insights into the effective prediction of dolphin aggregation.